Enhanced herbicidal compositions of transition metal chelates

ABSTRACT

The present invention relates to herbicidal compositions comprising a transition metal chelate; and a potassium-containing salt and/or a sodium-containing salt; wherein said composition has enhanced herbicidal activity when compared with an otherwise identical composition lacking said potassium-containing salt and/or said sodium-containing salt; as well as related methods and uses.

FIELD OF THE INVENTION

The present invention relates to herbicidal compositions and methods forcontrolling unwanted vegetation.

BACKGROUND

The selective control of unwanted vegetation, such as, for example,weeds, is a major industry. Vegetation can be controlled usingherbicides that are non-selective or selective, and systemic or contact.Non-selective herbicides kill or damage all plants to which they areapplied, i.e., both desired and undesired vegetation. In contrast,selective herbicides eliminate or inhibit the growth of unwantedvegetation, while leaving the desired vegetation relatively unharmed.Contact herbicides are applied to the top growth, or portion(s) of theplant located above the soil surface. In contrast, systemic herbicidesare initially taken up by the roots and/or the foliage of the plant andsubsequently translocated to tissues that are remotely located from thepoint of application.

At present, there are several common types of selective herbicides onthe market. The Phenoxy Acid-Type selective herbicides include 2,4-D(2,4-Dicholorophenoxyacetic acid), 2,4-DP (2,4-Dicholorophenoxypropionicacid, or Dichlorprop), and mecoprop (2-(2-methyl-4-chlorophenoxy)propionic acid). These systemic selective herbicides are initially takenup by the leaves, stem or roots of a plant, and subsequently movedthroughout the plant. 2,4-D and 2,4-DP stimulate nucleic acid andprotein synthesis and affect enzyme activity, respiration, and celldivision, while mecoprop affects enzyme activity and plant growth. TheBenzoic Acid-Type selective herbicides include dicamba, another systemicselective herbicide that is initially taken up by the leaves and rootsof a plant and subsequently moved throughout the plant. BenzoicAcid-Type selective herbicides are similar to the Phenoxy Acid-Typeselective herbicides described above.

Currently, these selective herbicides present major toxicological andenvironmental concerns. Attempts have been made to create selectiveherbicides that are effective, yet environmentally safe. WO 03/073856 A1(which is incorporated herein by reference in its entirety) relates to anew class of environmentally safe selective herbicides that includes atransition metal component (Fe, Cu, Zn and/or Mn) and a chelating agent(aminopolycarboxylate, salicylate and/or amino acid). These metalcomplexones can be applied over an area of established grass and turf inwhich broadleaf weeds are growing and selectively remove these weeds,leaving the grass unharmed.

While such environmentally safe selective herbicidal compositions havebeen shown to be effective, there is a need for environmentally safecompositions that demonstrate enhanced herbicidal efficacy (optionallyenhanced selective herbicidal efficacy) effective to control undesiredvegetation (e.g. weeds) without harming the desired vegetation (e.g.lawn grass). Enhanced herbicidal compositions may demonstrate a morerapid herbicidal effect, and may reduce the amount of herbicidal activeingredient required.

SUMMARY OF THE INVENTION

According to one aspect there is provided a herbicidal compositioncomprising:

-   a. a transition metal chelate; and-   b. a potassium-containing salt, a sodium-containing salt or a    combination thereof,    -   wherein said composition has enhanced herbicidal activity when        compared with an otherwise identical composition lacking said        potassium-containing salt, said sodium-containing salt or said        combination thereof.

In one aspect there is provided use of a potassium-containing salt,sodium-containing salt or a combination thereof, for enhancing theherbicidal activity of a transition metal chelate (when compared with anotherwise identical transition metal chelate lacking saidpotassium-containing salt, said sodium-containing salt or saidcombination thereof).

In one aspect there is provided use of a potassium-containing salt,sodium-containing salt or a combination thereof, for enhancing theselective herbicidal activity of a transition metal chelate (whencompared with an otherwise identical transition metal chelate lackingsaid potassium-containing salt, said sodium-containing salt or saidcombination thereof).

In one aspect the invention provides a method for controlling the growthof undesired vegetation, said method comprising providing:

-   a. a transition metal chelate; and-   b. a potassium-containing salt, a sodium-containing salt or a    combination thereof; and-   c. contacting undesired vegetation with said transition metal    chelate and said potassium-containing salt and/or said    sodium-containing salt,    -   wherein, following said contacting step, the undesired        vegetation is destroyed.

In one aspect the invention provides a method for selectivelycontrolling the growth of undesired vegetation, said method comprisingproviding:

-   a. a transition metal chelate; and a potassium-containing salt, a    sodium-containing salt or a combination thereof; and-   b. contacting desired and undesired vegetation with said transition    metal chelate and said potassium-containing salt and/or said    sodium-containing salt,    -   and wherein, following said contacting step, the undesired        vegetation is preferentially destroyed while growth of the        desired vegetation is relatively unharmed.

DETAILED DESCRIPTION

The present inventors have surprisingly discovered that use of apotassium-containing salt and/or a sodium-containing salt enhances (e.g.synergistically enhances) the herbicidal activity of a compositioncomprising a transition metal chelate.

Thus, in use of the invention, the potassium-containing salt and/or thesodium-containing salt enhances the herbicidal activity of thetransition metal chelate.

The transition metal chelate component and the potassium-containing saltand/or the sodium-containing salt are applied to a selected target areacontaining undesired vegetation (and optionally desired vegetation) in a“herbicidal effective amount”. Thus, when applied to the target area insaid amount, the transition metal chelate is able to contact with anddestroy undesired vegetation located within in the target area.Reference to ‘destroys’ is considered synonymous with, damaging beyondrecovery, (terminally) inhibiting or eliminating growth of the undesiredvegetation to which it is applied. When desired vegetation is alsopresent in the target area, undesired vegetation is preferentiallydestroyed while growth of the desired vegetation is relatively unharmed.In this regard, should accidental damage of desired vegetation occur,this is typically of a transient nature and the desired vegetation isable to recover. Occasionally, a very low incidence of accidental injuryor damage of desired vegetation may be observed. Whilst to be ideallyavoided, a skilled person would appreciate that such observations areconsidered synonymous with the term ‘unharmed/relatively unharmed’ asused herein.

In the context of the present invention, desired vegetation refers tograss, lawn, and/or pastureland, and preferably refers to a grass (e.g.a lawn grass). Particular examples include Perennial ryegrass (Loliumperenne L.), Kentucky bluegrass (Poa pratensis L.), Chewings fescue(Festuca rubra spp. Commutate), Creeping fescue (Festuca rubra spp.rubra/trichophylla), Tall fescue (Festuca arundinacea Schreb.), Bluefescue (Festuca glauca Villars.), Colonial bentgrass (Agrotis tenuisSibth), Annual bluegrass (Poa annua L.), Bermudagrass (Cynodondactylon), Centipedegrass (Eremochloa ophiuroides), St. Augustinegrass(Stenotaphrum secundatum), and Zoysia grass (Zoisia spp.).

In the context of the present invention, undesired vegetation maycomprise or consist of dandelions (e.g. Taraxacum officinale), falsedandelions (e.g. Hypochoeris radicata), white clover (e.g. Trifoliumrepens), daisies (e.g. English daisy Bellis perennis), chickweed (e.g.Stellaria media), and black medick (e.g. Medicago lupulina), mosses,liverworts, ferns, horsetails, conifers, dicotyledonous plants, algae orcombinations thereof. The undesired vegetation preferably comprises orconsists of a dandelion, a white clover or a combination thereof.

The composition can be used in both residential and commercial plant orcrop areas, and it is very effective against common weeds such asdandelions.

Transition metal chelates of, or for use in, the present invention mayinclude any transition metal chelates disclosed in WO 03/073856 and/orWO 2011/154541 (the teaching of which is incorporated herein byreference). Alternatively or additionally, the transition metal chelatesmay be formed using any of the methods disclosed in WO 03/073856 and/orWO 2011/154541.

The transition metal chelate can be formed using various techniquesknown in the art. For example, the transition metal ions can be in theform of a transition metal salt, such as transition metal chlorides,transition metal sulfates, transition metal nitrates, transition metalcitrates, transition metal phosphates, transition metal chelates,transition metal sulfides, transition metal sulfites, transition metalsuccinates, transition metal gluconates, transition metal lactates,transition metal formates, transition metal nitrites, transition metalsalicylates, transition metal carboxylic acids, or in combinations ofthese salts. The chelating agent can also have various forms. In oneembodiment, a chelating agent may be a free acid. In another embodimentthe chelating agent may be a salt. Commercially available metal chelatescan also be used.

Any suitable transition metal may be comprised in the transition metalchelate. In one embodiment the transition metal may comprise (or consistof) iron, copper, manganese, nickel, zinc or combinations thereof.Suitably, the transition metal for use in a transition metal chelateaccording to the invention may comprise (or consist of) iron.

Preferred chelating agents include EDTA, HEDTA, EDG, EDDS, GLDA, MGDA,isomers thereof, or combinations thereof, in particular EDTA and/orHEDTA.

In embodiments where an iron chelate is employed, the chelating agentmay be selected from hydroxyethylenediaminetriacetic acid,ethylenediaminetetraacetic acid, diamino cyclohexane tetraacetic acid,ethylenediamine disuccinic acid, ethanoldiglycine, methylglycinediaceticacid, gluconic acid, glutamicaciddiacetic acid,aminotri(methylenephosphonic acid), ethanoldiglycine,hydroxyethyldiphosphonic acid, iminodisuccinic acid, hydroxyiminodisuccinic acid or combinations thereof and/or salts thereof, inparticular FeEDTA and/or FeHEDTA. One of applicant's commercialproducts, FIESTA™ (which contains iron as an active ingredient, presentas FeHEDTA) is preferred.

Enhanced Herbicidal Activity

An assessment of “herbicidal activity” can be made using a “vegetationdamage assay” taught herein.

The “vegetation damage assay” comprises:

-   -   a. applying an amount of a composition or component thereof to        an area of vegetation;    -   b. following application (e.g. after at least 7 or 14 days from        application) assessing damage visually using a percentage rating        scale from 0 (no injury) to 100% (death); and    -   c. calculating percentage control using the Henderson & Tilton        formula.

In a preferred embodiment the undesirable vegetation is selected fromdandelion and/or white clover (optionally the desirable vegetation isselected from perennial rye grass).

Herbicidal activity is typically acknowledged when an amount of acomposition or component thereof (e.g. of a transition metal chelateherein) causes damage to vegetation that is rated at at least about 40%in the vegetation damage assay. A more commonly accepted herbicidalactivity corresponds to damage to vegetation that is rated at at leastabout 50% or 60% in the vegetation damage assay. A preferred herbicidalactivity corresponds to damage to vegetation that is rated at at leastabout 70% or 80% in the vegetation damage assay, and a desiredherbicidal activity corresponds to damage to vegetation that is rated atat least about 90% in the vegetation damage assay.

As hereinbefore discussed, the presence of a potassium-containing saltand/or a sodium-containing salt enhances the herbicidal activity of atransition metal chelate. Said enhanced herbicidal activity may bereadily confirmed via a simple comparative experiment employing the“vegetation damage assay” described above (and as illustrated in theExamples). In more detail, two compositions containing the sametransition metal chelate (one composition including apotassium-containing salt and/or a sodium-containing salt, and the othercomposition not including said potassium-containing salt and/or saidsodium-containing salt) are tested in parallel (under identical orotherwise experimentally equivalent conditions), and their respectivevegetation damage scores are compared. To ensure optimal comparativetesting, the amount of transition metal chelate applied per target area(i.e. grams of metal per m² or grams of metal chelate per m²) should bethe same for the two compositions being tested in parallel. By way ofexample, in one embodiment, the two compositions being tested employ thesame concentration of transition metal chelate, and each composition isapplied to an identical/equivalent target area (m²).

In one embodiment, the presence of a potassium-containing salt and/or asodium-containing salt enhances the herbicidal activity of a compositionof the present invention by at least 5% (e.g. corresponding to at leasta 5% score increase in a “vegetation damage assay” as described herein)when compared to an otherwise identical ‘control’ composition that doesnot comprise a potassium-containing salt and/or sodium-containing salt.

The present invention embraces adding a potassium-containing salt and/orsodium-containing salt to a transition metal chelate composition thathas no or substantially no herbicidal activity, such that following saidaddition the composition is now capable of demonstrating herbicidalactivity. This improvement is consistent with providing an enhancedherbicidal activity.

In one embodiment, the presence of a potassium-containing salt and/or asodium-containing salt enhances the herbicidal activity of a compositionof the present invention by at least 10% or by at least 15% (e.g.corresponding to at least a 10% or at least a 15% score increase in a“vegetation damage assay” as described herein) when compared to thecorresponding ‘control’ composition (no potassium-containing salt and/orsodium-containing salt).

In another embodiment, the presence of a potassium-containing saltand/or sodium-containing salt enhances the herbicidal activity of acomposition of the present invention by at least 20% or at least 30%(e.g. corresponding to at least a 20% or at least a 30% score increasein a “vegetation damage assay” as described herein) when compared to thecorresponding ‘control’ composition (no potassium-containing salt and/orsodium-containing salt).

Suitably, the presence of a potassium-containing salt and/orsodium-containing salt enhances the herbicidal activity of a compositionof the present invention by at least 40% or at least 50% (e.g.corresponding to at least a 40% or at least a 50% score increase in a“vegetation damage assay” as described herein) when compared to thecorresponding ‘control’ composition (no potassium-containing salt and/orsodium-containing salt).

For the avoidance of any doubt, the aforementioned reference to apotassium-containing salt and/or a sodium-containing salt embraces theaddition of only a potassium-containing salt, the addition of only asodium-containing salt, or addition of a combination of each of saidsalts.

Similarly, for the avoidance of any doubt, the aforementioned referenceto “enhanced herbicidal activity” in the context of a composition of thepresent invention embraces reference to the transition metal chelatecomponent thereof and the use thereof.

In one embodiment of the present invention a composition typicallycomprises a transition metal chelate (e.g. an iron chelate) at aconcentration of at least about 1% by weight to about 12% by weight.

In one embodiment of the present invention a composition of theinvention may comprise a transition metal (suitably iron) present asmetal chelate at a concentration of at least about 0.1% by weight toabout 5% by weight.

In one embodiment, a composition of the invention may comprise atransition metal (suitably iron) present as metal chelate at aconcentration between about 0.18% to about 5.0% by weight, suitably at aconcentration between about 0.18% to about 3% by weight.

As discussed above, the addition of potassium-containing salts and/orsodium-containing salts enhance the herbicidal activity efficacy of atransition metal chelate. Therefore, it is not intended that thepotassium-containing salt and/or sodium-containing salt is admixed witha transition metal chelate for the purpose (e.g. sole purpose) ofadjusting the pH of said admixture.

Preferably a sodium-containing salt is selected from sodium chloride,hepes sodium salt, sodium acetate anhydrous, sodium acetate trihydrate,sodium azide, sodium β-glycerophosphate, sodium benzoate, sodiumbicarbonate, sodium bisulphite, sodium borate decahydrate, sodiumborohydride, sodium bromide, sodium carbonate anhydrous, sodiumcarbonate decahydrous, sodium carbonate monohydrous, sodium chlorite,sodium iodide, sodium nitrate, sodium nitrite, sodium silicate, sodiumsulfate, sodium sulfite, sodium tripolyphosphate, sodium chloroacetate,sodium chlorate, sodium metabisulfite, sodium octanoate (NaC8), sodiumnonanoate (NaC9), sodium decanoate (NaC10), sodium octadecanoate(NaC18), or combinations thereof.

Preferably a sodium-containing salt is selected from sodium chloride,hepes sodium salt, sodium acetate anhydrous, sodium acetate trihydrate,sodium azide, sodium β-glycerophosphate, sodium benzoate, sodiumbicarbonate, sodium bisulphite, sodium borate decahydrate, sodiumborohydride, sodium bromide, sodium carbonate anhydrous, sodiumcarbonate decahydrous, sodium carbonate monohydrous, sodium chlorite,sodium iodide, sodium nitrate, sodium nitrite, sodium silicate, sodiumsulfate, sodium sulfite, sodium tripolyphosphate, sodium octanoate(NaC8), sodium nonanoate (NaC9), sodium decanoate (NaC10), sodiumoctadecanoate (NaC18), or combinations thereof.

Preferably a sodium-containing salt is selected from sodium chloride,hepes sodium salt, sodium acetate anhydrous, sodium acetate trihydrate,sodium azide, sodium β-glycerophosphate, sodium benzoate, sodiumbicarbonate, sodium bisulphite, sodium borate decahydrate, sodiumborohydride, sodium bromide, sodium carbonate anhydrous, sodiumcarbonate decahydrous, sodium carbonate monohydrous, sodium chlorite,sodium iodide, sodium nitrate, sodium nitrite, sodium silicate, sodiumsulfate, sodium sulfite, sodium tripolyphosphate, or combinationsthereof.

Preferably a sodium-containing salt is selected from sodium chloride,hepes sodium salt, sodium acetate anhydrous, sodium acetate trihydrate,sodium azide, sodium β-glycerophosphate, sodium benzoate, sodiumbicarbonate, sodium bisulphite, sodium borate decahydrate, sodiumborohydride, sodium bromide, sodium chlorite, sodium iodide, sodiumnitrate, sodium nitrite, sodium silicate, sodium sulfate, sodiumsulfite, sodium tripolyphosphate, (optionally sodium chloroacetate,sodium chlorate, or sodium metabisulfite) or combinations thereof.

Preferably a sodium-containing salt is selected from sodium chloride,hepes sodium salt, sodium acetate anhydrous, sodium acetate trihydrate,sodium azide, sodium β-glycerophosphate, sodium benzoate, sodiumbisulphite, sodium borate decahydrate, sodium borohydride, sodiumbromide, sodium chlorite, sodium iodide, sodium nitrate, sodium nitrite,sodium silicate, sodium sulfate, sodium sulfite, or sodiumtripolyphosphate, (optionally sodium chloroacetate, sodium chlorate, orsodium metabisulfite) or combinations thereof.

Preferably a sodium-containing salt is selected from sodium chloride,sodium acetate anhydrous, sodium acetate trihydrate, sodium benzoate,sodium bicarbonate, sodium bisulphite, sodium borate decahydrate, sodiumbromide, sodium chlorite, sodium nitrate, sodium nitrite, sodiumsilicate, sodium sulfate, sodium sulfite, or sodium tripolyphosphate,sodium chloroacetate, sodium chlorate, sodium metabisulfite, sodiumoctanoate (NaC8), sodium nonanoate (NaC9), sodium decanoate (NaC10),sodium octadecanoate (NaC18) or combinations thereof.

Preferably a sodium-containing salt is selected from sodium chloride,sodium acetate anhydrous, sodium acetate trihydrate, sodium benzoate,sodium bicarbonate, sodium bisulphite, sodium borate decahydrate, sodiumbromide, sodium chlorite, sodium nitrate, sodium nitrite, sodiumsilicate, sodium sulfate, sodium sulfite, or sodium tripolyphosphate,sodium chloroacetate, sodium chlorate, sodium metabisulfite, orcombinations thereof.

In one embodiment, a sodium-containing salt is not a sodium salt of afatty acid (e.g. not sodium nonanoate). Alternatively or additionally,in one embodiment a sodium-containing salt is not a sodium salt of achelating agent. Alternatively or additionally, in one embodiment asodium-containing salt is not sodium carbonate.

Preferably a potassium-containing salt is selected from potassiumchloride, potassium sulfate, potassium phosphate, potassium pelargonate,potassium citrate, potassium carbonate, potassium biphosphate, potassiumnitrate, mono potassium phosphate, potassium thiosulfate, (optionallypotassium amino acid complex or potassium chelate), potassium octanoate(KC8), potassium decanoate (KC10), potassium octadecanoate (KC18) orcombinations thereof. In a preferred embodiment, thepotassium-containing salt may be potassium chloride.

Preferably a potassium-containing salt is selected from potassiumchloride, potassium sulfate, potassium phosphate, potassium pelargonate,potassium citrate, potassium carbonate, potassium biphosphate, potassiumnitrate, mono potassium phosphate, potassium thiosulfate, (optionallypotassium amino acid complex or potassium chelate), or combinationsthereof. In a preferred embodiment, the potassium-containing salt may bepotassium chloride.

Preferably a potassium-containing salt is selected from potassiumchloride, potassium sulfate, potassium phosphate, potassium pelargonate,potassium citrate, potassium carbonate, potassium biphosphate, potassiumnitrate, mono potassium phosphate, potassium thiosulfate, (optionallypotassium amino acid complex), or combinations thereof. In a preferredembodiment, the potassium-containing salt may be potassium chloride.

Preferably a potassium-containing salt is selected from potassiumchloride, potassium sulfate, potassium phosphate, potassium citrate,potassium carbonate, potassium biphosphate, potassium nitrate, potassiumthiosulfate, potassium amino acid complex, potassium octanoate (KC8),potassium decanoate (KC10), potassium octadecanoate (KC18), orcombinations thereof.

Preferably a potassium-containing salt is selected from potassiumchloride, potassium sulfate, potassium phosphate, potassium citrate,potassium carbonate, potassium biphosphate, potassium nitrate, potassiumthiosulfate, potassium amino acid complex, or combinations thereof.

In one embodiment, a potassium-containing salt is not a potassium saltof a fatty acid (e.g. nonanoate). Preferably, a potassium-containingsalt is not potassium nonanoate. Alternatively or additionally, apotassium-containing salt is not a potassium salt of a chelating agent.

The potassium-containing salt and/or sodium-containing salt may be addedto the herbicidal composition at the time of formulation, or it can beprovided as a separate composition that is admixed with one or morefurther ingredient(s) prior to or during application to vegetation.Alternatively or additionally, said potassium-containing salt and/orsodium-containing salt may be applied separately to vegetation.

In one embodiment the potassium-containing salt may be a chlorinatedpotassium-containing salt. In another embodiment, the sodium-containingsalt may be a chlorinated sodium-containing salt. In a furtherembodiment, the potassium-containing salt may be a chlorinatedpotassium-containing salt and the sodium-containing salt may be achlorinated sodium-containing salt.

A composition of the present invention may comprise apotassium-containing salt and a sodium-containing salt at aconcentration between about 0.5% to about 25% by weight, suitably at aconcentration between about 1% to about 25% by weight. Suitably acomposition the present invention may comprise a potassium-containingsalt and a sodium-containing salt at a concentration of between about 5%to about 25% by weight or between about 10% to about 25%.

In another embodiment a composition the present invention may comprise apotassium-containing salt and a sodium-containing salt at aconcentration between about 0.5% to about 15% by weight, suitably at aconcentration between about 0.5% to about 10% by weight.

In a further embodiment a composition of the present invention maycomprise a potassium-containing salt and a sodium-containing salt at aconcentration between about 0.01% to about 25% by weight, or betweenabout 1% to about 22% by weight. Suitably between about 5% to about 20%by weight, more suitably between about 10% to about 15% by weight.

In a yet further embodiment a composition of the present invention maycomprise a potassium-containing salt and a sodium-containing salt at aconcentration of at least 5% by weight or at least 10% by weight.Suitably, a composition of the present invention may comprise the use ofa potassium-containing salt and a sodium-containing salt at aconcentration of at least 15% by weight or at least 20% by weight. Insome embodiments a composition of the present invention may comprise apotassium-containing salt and a sodium-containing salt at aconcentration of at least 25% or at least 30% by weight.

A composition of the present invention may comprise a sodium-containingsalt or a potassium-containing salt at a concentration between about0.5% to about 25% by weight, suitably at a concentration between about1% to about 25% by weight. Suitably a composition of the presentinvention may comprise a sodium-containing salt or apotassium-containing salt at a concentration of between about 5% toabout 25% by weight or between about 10% to about 25%.

In another embodiment a composition of the present invention maycomprise a sodium-containing salt or a potassium-containing salt at aconcentration between about 0.5% to about 15% by weight, suitably at aconcentration between about 0.5% to about 10% by weight.

In a further embodiment a composition of the invention may comprise asodium-containing salt or a potassium-containing salt at a concentrationbetween about 0.01% to about 25% by weight, or between about 1% to about22% by weight. Suitably between about 5% to about 20% by weight, moresuitably between about 10% to about 15% by weight.

In a yet further embodiment a composition of the present invention maycomprise a sodium-containing salt or a potassium-containing salt at aconcentration of at least 5% by weight or at least 10% by weight.Suitably, a composition of the invention may comprise asodium-containing salt or a potassium-containing salt at a concentrationof at least 15% by weight or at least 20% by weight. In some embodimentsa composition of the invention may comprise a sodium-containing salt ora potassium-containing salt at a concentration of at least 25% or atleast 30% by weight.

Optionally, a composition of the invention (e.g. a compositioncomprising a potassium-containing salt) may comprise no (orsubstantially no) sodium-containing salt. For example, a composition ofthe invention may not comprise a sodium-containing salt selected fromsodium chloride, hepes sodium salt, sodium acetate anhydrous, sodiumacetate trihydrate, sodium azide, sodium β-glycerophosphate, sodiumbenzoate, sodium bicarbonate, sodium bisulphite, sodium boratedecahydrate, sodium borohydride, sodium bromide, sodium carbonateanhydrous, sodium carbonate decahydrous, sodium carbonate monohydrous,sodium chlorite, sodium iodide, sodium nitrate, sodium nitrite, sodiumsilicate, sodium sulfate, sodium sulfite, or sodium tripolyphosphate,sodium chloroacetate, sodium chlorate, sodium metabisulfite, sodiumoctanoate (NaC8), sodium nonanoate (NaC9), sodium decanoate (NaC10),sodium octadecanoate (NaC18), or combinations thereof. Suitably acomposition of the invention may not comprise a sodium-containing saltselected from sodium chloride, hepes sodium salt, sodium acetateanhydrous, sodium acetate trihydrate, sodium azide, sodiumβ-glycerophosphate, sodium benzoate, sodium bicarbonate, sodiumbisulphite, sodium borate decahydrate, sodium borohydride, sodiumbromide, sodium carbonate anhydrous, sodium carbonate decahydrous,sodium carbonate monohydrous, sodium chlorite, sodium iodide, sodiumnitrate, sodium nitrite, sodium silicate, sodium sulfate, sodiumsulfite, or sodium tripolyphosphate, or combinations thereof. Suitably,a composition of the invention (e.g. a composition comprising apotassium-containing salt) may not comprise sodium chloride.

The term “substantially no” as used in this context means less than0.01% or less than 0.001% sodium-containing salt by weight. Preferablythe term “suitably no” may mean less than 0.0001% sodium-containing saltby weight.

The end-use concentration of the ingredients of the herbicidalcompositions of the present invention may vary depending on the form ofthe metal chelate and the potassium-containing salt and/orsodium-containing salt.

When referring to the amount, e.g., concentration and molar ratio, ofthe metal component in the composition, the amount is based on theamount of metal ions present within the metal component.

The compositions of the invention may be formulated as a liquid formula,a dry granule, a liquid concentrate, or a dry concentrate.

In one embodiment a composition of the invention may be provided as adry concentrate that is dissolved in water before application tovegetation.

In another embodiment a composition of the invention may be provided asa liquid concentrate that is diluted with water before application tovegetation.

In a further embodiment a composition of the invention may be providedas a dry granule that is applied directly to the vegetation.

In one embodiment, a composition of the invention may be formulated as aready-to-use formulation. Such formulations may take the form of liquidor dry RTU formulations (preferably a liquid RTU formulation).

The solvents used in the ready-to-use liquid composition and liquidconcentrate forms can vary. In one embodiment the solvent may be a poorwetting agent on plant leaves, essentially equal to that of water. Grassleaves are often vertical and hard to wet, whereas many weeds, such asthe dandelion, are horizontal and easier to wet. Without wishing to bebound by theory, solutions that are poor wetting agents are believed tobe advantageous as they tend to bead up and run off of grass leaves,while spreading onto leaves of the horizontal weeds, such as dandelionweeds. Suitably, a solvent used in the formulation of the disclosedherbicidal compositions may be selected from propylene glycol, glycerin,alcohols (e.g. tetrahydrofurfuryl alcohol (THFA)) or combinationsthereof.

In one embodiment a RTU composition of the invention (e.g. a liquid RTUcomposition) may comprise a transition metal chelate (e.g. an ironchelate) at a concentration of at least 1% by weight (e.g. up to about12% by weight). Suitably a transition metal chelate (suitably iron) maybe present at a concentration of at least 3% by weight, more suitably atleast about 5% by weight. A preferred RTU liquid formulation of thepresent invention comprises between 1% and 2% (approximately 1.5%) byweight iron chelate (e.g. FeHEDTA or FeEDTA). In other embodiments a RTUcomposition of the invention may comprise a transition metal chelate(e.g. an iron chelate) at a concentration of at least 7% by weight,suitably at least 10% by weight.

In one embodiment a metal chelate may be present within a RTUcomposition of the invention (e.g. a solid RTU composition) at aconcentration between about 3% to about 12% by weight. Suitably, themetal chelate may be present at a concentration between about 3% toabout 10% or between about 3% to about 8%. One preferred RTU solidformulation of the present invention (e.g. a fertilizer-basedformulation) comprises between about 6% and about 8% by weight(approximately 7% by weight) iron chelate (e.g. FeEDTA or FeHEDTA).Another preferred RTU solid formulation of the present invention (e.g. asolid bait) comprises between about 3% and 6% by weight (approximately4.8% by weight) iron chelate (e.g. FeEDTA or FeHEDTA).

In other embodiments the metal chelate may be present in a RTUcomposition at a concentration between about 5% to about 12% by weight,suitably between about 7% to about 12% by weight.

In one embodiment a RTU composition of the invention may comprise atransition metal (suitably iron) present as a metal chelate at aconcentration of at least 0.1% by weight. Suitably a transition metal(suitably iron) may be present at a concentration of at least 1% byweight, more suitably at least about 5% by weight.

In one embodiment a transition metal (suitably iron) present as a metalchelate_may be present in a RTU composition of the present invention ata concentration between about 0.18% to about 5.0% by weight, suitably ata concentration between about 0.18% to about 3% by weight. Suitably thetransition metal may be present at a concentration of between about 0.2%to about 2.0% by weight.

In another embodiment, a transition metal (suitably iron) present as ametal chelate may be present in a RTU composition of the presentinvention at a concentration between about 1% to about 5.0% by weight,suitably at a concentration between about 2% to about 5% by weight.

In a further embodiment, a RTU composition may comprise a transitionmetal (suitably iron) present as a metal chelate at a concentrationbetween about 0.2% to about 1.5% by weight, suitably between about 0.2%to about 1% or between about 0.5% to about 1.5% by weight.

A RTU composition of the present invention may comprise apotassium-containing salt and/or a sodium-containing salt ashereinbefore described.

Alternatively or in addition to the above ingredients, in one embodimenta composition of the invention may be formulated with one or morefurther components. For example, the composition may be formulated withone or more component selected from growth regulators, fertilizers,herbicides, thickening agents, humectants, antioxidants, stabilizingagents, wetting agents, sequestrants, solvents, dyes, or combinationsthereof.

Suitable humectants may include propylene glycol, glycerin, beetmolasses, or combinations thereof. Suitable antioxidants may includecitric acid. Suitable stabilizing agents may include citric acid,ammonium compounds, or combinations thereof. Suitable wetting agents mayinclude carboxylic acids (or salts thereof) or silicone polymers (e.g.Silwet 77 (Witco Corp, CT, USA)). Suitable preservatives may includeKathon® (a mixture of 5-chloro-2-methyl-4-isothiazolin-3-one and2-methyl-4-isothiazolin-3-one, made by Rohm & Haas of Hayward, Calif.),sorbic acid, sodium benzoate, sodium propionate, parabens, isopropylalcohol, ethanol or combinations thereof. The end-use concentration ofsuch additives may vary, but in some embodiments, the concentration maybe between about 0.1 to about 5% by weight.

A variety of fertilizers can be added to the herbicidal composition ofthe present invention. Preferably, the fertilizer is anitrogen-containing fertilizer that is effective to promote the rapidgrowth of grass, thereby allowing the grass to shade and out-compete thedamaged weeds. Suitably the composition of the invention may beformulated with a fertilizer, such as a fertilizer selected from ureaammonium nitrate, ammonium sulfate, leather meal, bone meal, plantmeals, ammonium potassium phosphate, or combinations thereof.

Any end use concentration of a fertilizer is contemplated in the presentinvention. In one embodiment a fertilizer may be added to a compositionof the present invention with an end use concentration in the range ofabout 20% to about 80% by weight, suitably in the range of about 50 toabout 75% by weight, preferably in the range of 60 to 75% by weight.

In some embodiments one or more growth regulators may be added to acomposition of the present invention. By way of non-limiting example,the growth regulators added to the herbicidal compositions may includemaleic hydrazide (MH), cycocel (2-chloroethyl-trimethyl ammoniumchloride), auxin derivatives, and combinations thereof. The end-useconcentration of the additional growth regulators can vary. In oneembodiment the concentration may be between about 100 ppm to about 2% byweight.

The herbicidal compositions of the present invention may also includenatural growth regulators, such as for example, salicylic acid, salts ofsalicylic acid including ammonium salicylate, jasmonates, ethylene,auxins, gibberellins, cytokinins, abscisic acid, or combinationsthereof. The end-use concentration of these natural growth regulatorscan vary, but in some embodiments may be between about 10 ppm to about5% by weight.

In addition to the transition metal chelates disclosed herein, acomposition of the invention may comprise one or more furtherherbicidally effective ingredients (e.g. a co-active ingredient). In oneembodiment the one or more further herbicidally effective ingredientsmay be selected from glyphosate, glufosinate, ammonium pelargonate,pelargonic acid, medium chain fatty acids and their salts, urea, sodium,borax, copper sulfate, carboxylic acids or the salts thereof, ammoniumcompounds, calcium compounds, or combinations thereof. The end-useconcentration of the additional herbicide(s) can vary, but in someembodiments, the concentration may be between about 0.5% to about 5% byweight, suitably between about 2% to about 5% by weight.

Furthermore, a variety of thickening agents may be added to theherbicidal compositions disclosed herein. Suitable thickening agents mayinclude Rhodopol 23 (Rhone Poulenc), VanGel B (R. T. Vanderbilt), KelzanS (Merck & Co.), guar gum, propylene glycol, glycerol, and combinationsthereof. The end-use concentration of added thickening agent(s) canvary, but in some embodiments may be in the range of between about 0.01%to about 10% by weight.

The herbicidal compositions of the present invention are effective overa wide range of pH values. The person skilled in the art is capable ofdetermining an optimal pH of a composition of the invention. Forexample, once a composition of the invention has been appropriatelyformulated, the pH of the solution may be measured and adjusted asnecessary. The pH values can be measured using standard techniques. Forexample using a pH meter (suitably a pH meter with glass bulbelectrodes).

In one embodiment, the pH of a composition of the present invention maybe between about pH 1.5 to about pH 10. Suitably the pH of a compositionof the invention may be between about pH 4 to about pH 8.

In one embodiment a liquid ready-to-use (RTU) formulation according tothe present invention may comprise (or consist of):

  1.5% FeHEDTA 1.5% potassium chloride 0.08% sodium citrate stabilizer0.07% Kathon CG preservative 96.85% deionized water

Further additives, if used, such as fertilizers may be admixed withfurther agitation.

In another embodiment a (RTU) formulation according to one embodiment ofthe present invention may comprise (or consist of):

  7.0% FeEDTA 20.0% potassium chloride 28.0% bone and plant meals 25.0%ammonium sulfate 20% powdered sugar

In one embodiment a liquid ready-to-use (RTU) formulation according tothe present invention may comprise (or consist of):

  1.5% FeHEDTA 2.0% sodium sulfate 0.08% sodium citrate stabilizer 0.07%Kathon CG preservative 96.35% deionized water

Further additives, if used, such as fertilizers may be admixed withfurther agitation.

In another embodiment a (RTU) formulation according to one embodiment ofthe present invention may comprise (or consist of):

  7.0% FeEDTA 20.0% sodium sulfate 28.0% bone and plant meals 25.0%ammonium sulfate 20% powdered sugar

The RTU formulation may be prepared by admixing water and FeHEDTAconcentrate with agitation. Once thoroughly mixed, potassium chloride,stabilizer sodium citrate, and preservative Kathon CG may be admixed andthe composition agitated until the solution is homogeneous.

In one embodiment, a RTU formulation of the invention may be applied toundesired vegetation and optionally to desired vegetation (e.g. sprayed,using a hand sprayer, for example) at various rates.

In one embodiment, the solution may be applied (e.g. sprayed) toundesired vegetation and optionally to desired vegetation at a rate inthe range of about 0.2 g Fe/m² to 2.0 g Fe/m². Suitably, the solutionmay be applied (e.g. sprayed) in the range of about 0.25 g Fe/m² to 1.8g Fe/m², more preferably at a rate of about 0.5 g Fe/m².

When applied to undesired vegetation alone (or where loss of residualdesired vegetation is not important) higher application rates may beemployed, such as greater than 2.0 g Fe/m². For example, applicationrates in the region of 3-5 g Fe/m² or greater may be employed.

In some embodiments a RTU dry formulation may be prepared by admixing apotassium salt (such as potassium chloride or potassium sulfate) and/ora sodium salt and a dry Fe chelate powder.

Further additives, if used, such as fertilizers may be admixed to give0.2 to 2.0% Fe by weight of the final RTU composition. In someembodiments, where a RTU dry formulation is used, said formulation maybe applied to both desired and undesired vegetation using a spreader orany other application equipment at various rates. In one embodiment, theformulation may be applied at a rate in the range of 0.25 to 1.8 gFe/m², suitably at a rate of about 0.5 g Fe/m².

The term “selectively herbicidal” (aka “selectively treating/controllingundesired vegetation”) as used herein means that a composition of thepresent invention is capable of destroying undesired vegetation to whichit is applied, whilst leaving desired vegetation unharmed or relativelyunharmed. The term “selective herbicide” is opposite to “non-selectiveherbicide”, which destroy all or substantially all vegetation to whichit is applied, irrespective of whether said vegetation is desired orundesired vegetation.

An assessment of “selective herbicidal activity” can be made using a“selective herbicide assay” as taught herein.

The “selective herbicide assay” comprises:

-   -   a. applying an amount of a composition or component thereof to        an area of undesired vegetation and desired vegetation;    -   b. following application (e.g. after at least 7 or 14 days from        application) assessing plant damage visually using a percentage        rating scale from 0 (no injury) to 100% (death); and    -   c. calculating percentage control using the Henderson & Tilton        formula for the undesired vegetation and desired vegetation.

In a preferred embodiment the undesirable vegetation is selected fromdandelion and/or white clover, and the desirable vegetation is selectedfrom perennial rye grass.

A “selective herbicide activity” is typically acknowledged when anamount of a composition or component thereof (e.g. a transition metalchelate herein) scores a rating of at least about 40% (suitably at leastabout 50%, 60% or 70%) when applied to undesired vegetation, and scoresa rating of less than about 15% when applied to desired vegetation.

In one embodiment a selective herbicidal activity corresponds to arating of at least about 40% when applied to undesired vegetation, andscores a rating of less than about 10% or 5% (suitably less than about1%) when applied to desired vegetation.

In one embodiment a selective herbicidal activity corresponds to arating of at least about 60% when applied to undesired vegetation, andscores a rating of less than about 10% or 5% (suitably less than about1%) when applied to desired vegetation.

In one embodiment a selective herbicidal activity corresponds to arating of at least about 80% when applied to undesired vegetation, andscores a rating of less than about 10% or 5% (suitably less than about1%) when applied to desired vegetation.

In one embodiment a selective herbicidal activity corresponds to arating of at least about 90% when applied to undesired vegetation, andscores a rating of less than about 10% or 5% (suitably less than about1%) when applied to desired vegetation.

In one embodiment a selective herbicidal activity corresponds to arating of at least about 95% when applied to undesired vegetation, andscores a rating of less than about 10% or 5% (suitably less than about1%) when applied to desired vegetation.

As hereinbefore discussed, the presence of a potassium-containing saltand/or a sodium-containing salt may simultaneously enhance the selectiveherbicidal activity of a transition metal chelate. Said enhancedselective herbicidal activity may be readily confirmed via a simplecomparative experiment employing the “selective herbicide assay”described above (and as illustrated in the Examples). In more detail,two compositions containing the same transition metal chelate (onecomposition including a potassium-containing salt and/or asodium-containing salt, and the other composition not including saidpotassium-containing salt and/or said sodium-containing salt) are testedin parallel (under identical or otherwise experimentally equivalentconditions), and their respective undesired vegetation damage anddesired vegetation scores are compared. To ensure optimal comparativetesting, the amount of transition metal chelate applied per target area(i.e. grams of metal per m² or grams metal chelate per m²) should be thesame for the two compositions being tested in parallel. By way ofexample, in one embodiment, the two compositions being tested employ thesame concentration of transition metal chelate, and each composition isapplied to an identical/equivalent target area (m²).

The term “enhanced selective herbicidal activity” as used herein isconfirmed (for example, via the “selective herbicide assay” herein) whena composition of the invention demonstrates an increased differencebetween the % damage scores to desired vegetation and undesiredvegetation when compared to the corresponding difference recorded for a‘control’ composition comprising the same transition metal chelatelacking said potassium-containing salt and/or said sodium-containingsalt. To ensure optimal comparative assessment, identical metal chelate(g/m²) application rates should be employed (as discussed hereinbefore,for example with reference to the “vegetation damage assay”).

In other words, if (hypothetically) a composition of the presentinvention scores a rating of 40% activity against undesired vegetationand a score of 15% against desired vegetation (e.g. as determined in the“selective herbicide assay” herein) providing a difference of 25%,whereas if (hypothetically) a ‘control’ composition (otherwise identicalthough lacking said potassium-containing salt and/or saidsodium-containing salt) scores a rating of 35% activity againstundesired vegetation and a score of 18% against desired vegetation (e.g.as determined in the “selective herbicide assay” herein) providing adifference of 17%, then comparatively the composition of the inventionwould be considered to have enhanced selectively herbicidal activity.

Thus, in one embodiment the term “enhanced selective herbicidalactivity” as used herein means that a composition of the inventionprovides an increase in the difference between the % damage to desiredvegetation and undesired vegetation (e.g. as determined in the“selective herbicide assay” herein) of at least about 1% or at leastabout 3% when compared with the corresponding ‘control’ composition(otherwise identical though lacking said potassium-containing saltand/or said sodium-containing salt).

In another embodiment the term “enhanced selective herbicidal activity”as used herein means that a composition of the invention provides anincrease in the difference between the % damage to desired vegetationand undesired vegetation (e.g. as determined in the “selective herbicideassay” herein) of at least about 5% or at least about 10% when comparedwith the corresponding ‘control’ composition (otherwise identical thoughlacking said potassium-containing salt and/or said sodium-containingsalt).

Suitably, the term “enhanced selective herbicidal activity” as usedherein means that a composition of the invention provides an increase inthe difference between the % damage to desired vegetation and undesiredvegetation (e.g. as determined in the “selective herbicide assay”herein) of at least about 20% or at least about 30% or at least about50% when compared with the corresponding ‘control’ composition(otherwise identical though lacking said potassium-containing saltand/or said sodium-containing salt).

Suitably, the term “enhanced selective herbicidal activity” as usedherein means that a composition of the invention provides an increase inthe difference between the % damage to desired vegetation and undesiredvegetation (e.g. as determined in the “selective herbicide assay”herein) of at least about 70% or at least about 80% when compared withthe corresponding ‘control’ composition (otherwise identical thoughlacking said potassium-containing salt and/or said sodium-containingsalt).

For the avoidance of any doubt, the aforementioned reference to apotassium-containing salt and/or a sodium-containing salt embraces theaddition of only a potassium containing salt, the addition of only asodium-containing salt, or addition of a combination of each of saidsalts.

Similarly, for the avoidance of any doubt, the aforementioned referenceto “enhanced selective herbicidal activity” in the context of acomposition of the present invention embraces reference to thetransition metal chelate component thereof and the use thereof.

The present invention also provides a method for controlling the growthof undesired vegetation and/or for selectively controlling/treatingundesired vegetation, as hereinbefore described.

In one embodiment a herbicidal composition of the present invention maybe employed in said methods.

Alternatively or additionally, a transition metal chelate and apotassium-containing salt and/or sodium containing salt may be employedin said methods. For example, the methods of the invention may becarried out by contacting undesired vegetation (and optionally desiredvegetation) with the transition metal chelate component eithersimultaneously with, prior to or subsequent to the potassium-containingsalt and/or the sodium-containing salt component. In use, saidtransition metal component and said potassium-containing salt and/or thesodium-containing salt combine/cooperate and thereby deliver aherbicidal effective amount of transition metal chelate to the undesiredvegetation. Said herbicidal effective amount is typically measured interms of grams metal/m² (e.g. Fe g/m²) as hereinbefore described.

The term “contacting” as used in reference to a method of the inventionencompasses all methods for contacting or applying a composition, ortransition metal chelate and potassium-containing salt and/orsodium-containing salt to an area of vegetation known to the personskilled in the art. Contacting may include contacting vegetationdirectly and/or contacting the ground in which said vegetation ispresent.

Preferably a composition, or transition metal chelate andpotassium-containing salt and/or sodium-containing salt is applied tothe top growth, or portion(s) of the undesired vegetation (andoptionally to the desired vegetation) located above the soil surface.

In one embodiment, contacting may include spraying. Accordingly, themetal chelate component and the salt component are sprayed on undesiredvegetation (and optionally on desired vegetation). This application mayencompass both spraying the vegetation directly (e.g. on the top growth,or portion(s) of the plant located above the soil surface) and/orspraying the ground in which said vegetation is present.

In one embodiment the metal chelate component and the salt component areprovided as a dry concentrate that is dissolved in water beforeapplication to vegetation.

In one embodiment the metal chelate component and the salt component areprovided as a liquid concentrate that is diluted with water beforeapplication to vegetation.

In one embodiment the metal chelate component and the salt component areprovided as a dry granule that is applied directly to the vegetation.

In one embodiment the metal chelate component and the salt component areapplied to a grass lawn. Thereafter, the present invention selectivelycontrols the growth of undesirable vegetation (as hereinbeforedescribed) that may be present within the grass lawn.

Advantages

The present inventors have surprisingly found that the presence ofpotassium-containing salts and/or sodium-containing salts when employedin combination with a transition metal chelate demonstrate improvedherbicidal properties (e.g. improved selectively herbicidal properties).Without wishing to be bound by any theory, the present inventors believethat the added potassium-containing salt and/or sodium-containing saltcomponent of the present invention help improve metal (e.g. iron)chelate uptake by undesired vegetation (as hereinbefore defined) byprecipitating calcium ions (that would be antagonistic with metal)available in water and/or on the leaf surface of undesired vegetation.

The inventors have demonstrated the enhancement of herbicidal activity(e.g. enhanced selectively herbicidal activity)—see the accompanyingExamples. Such enhancement may advantageously be a synergisticenhancement.

By providing a composition having enhanced herbicidal activity (e.g.enhanced selectively herbicidal activity) a reduced amount of saidcomposition needs to be used when contacting an area of undesiredvegetation and/or an area of undesired vegetation and desiredvegetation. Advantageously, the ability to use a reduced amount of saidcomposition reduces costs associated with contacting an area ofundesired vegetation and/or an area of undesired vegetation and desiredvegetation, and/or results in improved efficiency of said composition.Also, a composition having enhanced selectively herbicidal activity maymean that an increased concentration of said composition can be appliedto an area of undesired and desired vegetation, advantageously resultingin increased damage and/or kill and/or inhibition of growth of undesiredvegetation and whilst demonstrating relatively reduced damage and/orkill and/or inhibition of growth of desired vegetation.

This disclosure is not limited by the exemplary methods and materialsdisclosed herein, and any methods and materials similar or equivalent tothose described herein can be used in the practice or testing ofembodiments of this disclosure. Numeric ranges are inclusive of thenumbers defining the range.

Suitable chelating agents of the present invention are described below.

A chelating agent is an organic molecule that can trap or encapsulatecertain trace metal cations to prevent the cations from entering intounwanted chemical reactions and forming insoluble salts. Without wishingto be bound by theory, the chelating agent complexes the metal ions intoa soluble but bound form, thus forming a metal chelate that is highlysoluble in water and that can be readily taken up by vegetation.

Various chelating agents can be used to form the metal chelate.Typically, a chelating agent is a substance in which the moleculesthereof form more than one bond to a single metal ion.

In other words, a chelating agent is typically a multidentate ligand.

In one embodiment a chelating agent may be selected from aconitic acid,alanine diacetic acid (ADA), alkoyl ethylene diamine triacetic acids(e.g., lauroyl ethylene diamine triacetic acids (LED3A),aminotri(methylenephosphonic acid) (ATMP), asparticaciddiacetic acid(ASDA), asparticacidmonoacetic acid, diamino cyclohexane tetraaceticacid (CDTA), citraconic acid, citric acid, 1,2-diaminopropanetetraaceticacid (DPTA-OH), 1,3-diamino-2-propanoltetraacetic acid (DTPA),diethanolamine, diethanol glycine (DEG), diethylenetriaminepentaaceticacid (DTPA), diethylene triamine pentamethylene phosphonic acid (DTPMP),diglycolic acid, dipicolinic acid (DPA), ethanolaminediacetic acid,ethanoldiglycine (EDG), ethionine, ethylenediamine (EDA),ethylenediaminediglutaric acid (EDDG),ethylenediaminedi(hydroxyphenylacetic acid (EDDHA),ethylenediaminedipropionic acid (EDDP), ethylenediaminedisuccinate(EDDS), ethylenediaminemonosuccinic acid (EDMS),ethylenediaminetetraacetic acid (EDTA), ethylenediaminetetrapropionicacid (EDTP), ethyleneglycolaminoethylestertetraacetic acid (EGTA),gallic acid, glucoheptonic acid, gluconic acid, glutamicaciddiaceticacid (GLDA), glutaric acid, glyceryliminodiacetic acid,glycinamidedisuccinic acid (GADS), glycoletherdiaminetetraacetic acid(GEDTA), 2-hydroxyethyldiacetic acid, hydroxyethylenediaminetriaceticacid (HEDTA), hydroxyethyldiphosphonic acid (HEDP), 2-hydroxyethyl iminodiacetic acid (HIMDA), hydroxyiminodiacetic acid (HIDA), hydroxyiminodisuccinic acid (HIDS), 2-hydroxy propylene diamine disuccinic acid(HPDDS), iminodiacetic acid (IDA), iminodisuccinic acid (IDS), itaconicacid, lauroyl ethylene diamine triacetic acids (LED3A), malic acid,malonic acid, methylglycinediacetate (MGDA), methyliminodiacetic acid(MIDA), monoethanolamine, nitrilotriacetic acid (NTA),nitrilotripropionic acid (NPA), N-phosphonomethyl glycine (glyphosate),propyldiamine tetraacetic acid (PDTA), salicylic acid, serinediaceticacid (SDA), sorbic acid, succinic acid, sugars, tartaric acid, tartronicacid, triethanolamine, triethylenetetraamine, triethylene tetraaminehexaacetic acid (TTHA), (or salts thereof) or combinations thereof.

In another embodiment a chelating agent may be selected from2-propanoltetraacetic acid, diethylenetriaminepentaacetic acid,ethanolaminediacetic acid, ethanoldiglycine, ethionine,ethylenediaminediglutaric acid, ethylenediaminedihydroxyphenylaceticacid, ethylenediaminedipropionic acid, ethylenediaminedisuccinic acid,ethylenediaminemonosuccinic acid, cid, 1,3-diamino-2-propanoltetraaceticacid, diethylenetriaminepentaacetic acid, ethanolaminediacetic acid,ethanoldiglycine, ethionine, ethylenediaminediglutaric acid,ethylenediaminedihydroxyphenylacetic acid, ethylenediaminedipropionicacid, ethylenediaminedisuccinic acid, ethylenediaminemonosuccinic acid,ethylenediaminetetraacetic acid,ethyleneglycolaminoethylestertetraacetic acid, glutamicaciddiaceticacid, glyceryliminodiacetic acid, glycinamidedisuccinic acid,glycoletherdiaminetetraacetic acid, 2-hydroxyethyldiacetic acid,hydroxyethylenediaminetriacetic acid, hydroxyiminodiacetic acid,iminodiacetic acid, iminodisuccinic acid, lauroyl ethylene diaminetriacetic acid, methylglycinediacetic acid, methyliminodiacetic acid,nitrilotriacetic acid, nitrilotripropionic acid, salicylic acid,serinediacetic acid (or the salts thereof) or combinations thereof.

Other suitable chelating agents include aminopolycarboxylic acid,amines, amides, phosphonic acid, or combinations thereof. Amino acidsmay also be used as chelating agents. Suitable amino acids may includealanine, arginine, asparagine, aspartic acid, glutamic acid, glutamine,glycine, histidine, isoleucine, leucine, lysine, methionine, proline,serine, threonine, tyrosine, valine, or combinations thereof. Otherchelating agents that may be used include beet molasses, carboxylicacids or the salts thereof, salicylic acid or the salts thereof (such asammonium salicylate), citric acid, or combinations thereof.

In certain embodiments, chelating agents that are more readilybiodegradable may be used in the compositions of the invention. Suchchelating agents may include ATMP, EDG, EDDS, GLDA, HEDP, MGDA, IDS, orHIDS. Other readily biodegradable chelating agents may include citricacid, gallic acid, glutaric acid, malic acid, salicylic acid, sorbicacid, succinic acid, sugars, tartaric acid or combinations thereof.Alternatively or additionally, such biodegradable chelating agents maybe selected from alanine, arginine, asparagine, aspartic acid, glutamicacid, glutamine, glycine, histidine, isoleucine, leucine, lysine,methionine, proline, serine, threonine, tyrosine, valine or combinationsthereof.

In one embodiment the chelator comprised in the transition metal chelatemay comprise (or consist of) an aminopolycarboxylate chelating agent.Suitably, an aminopolycarboxylate chelating agent may be selected fromhydroxyethylenediaminetriacetic acid, ethylenediaminetetraacetic acid,diamino cyclohexane tetraacetic acid, ethylenediamine disuccinic acid,ethanoldiglycine, methylglycinediacetic acid, glutamicaciddiacetic acid,or combinations thereof and/or salts thereof.

In another embodiment a chelating agent may be selected from diaminocyclohexane tetra-acetic acid, ethylenediaminedisuccinic acid,ethylenediaminetetraacetic acid, ethanol-diglycine,hydroxyethylenediaminetriacetic acid, methylglycinediacetic acid,glutamic-acid diacetic acid, diethylenetriaminepentaacetic acid,iminodisuccinic acid, their salts, or combinations thereof.

In one embodiment a composition of the invention may comprise:

-   -   a transition metal component, a chelating agent selected from        alanine diacetic acid, alkoyl ethylene diamine triacetic acid,        aminotri(methylenephosphonic acid), asparticaciddiacetic acid,        asparticacidmonoacetic acid, diamino cyclohexane tetraacetic        acid, citraconic acid, citric acid,        1,2-diaminopropanetetraacetic acid,        1,3-diamino-2-propanoltetraacetic acid,        diethylenetriaminepentaacetic acid, ethanolaminediacetic acid,        ethanoldiglycine, ethionine, ethylenediaminediglutaric acid,        ethylenediaminedihydroxyphenylacetic acid,        ethylenediaminedipropionic acid, ethylenediaminedisuccinic acid,        ethylenediaminemonosuccinic acid, ethylenediaminetetraacetic        acid, ethyleneglycolaminoethylestertetraacetic acid,        glutamicaciddiacetic acid, glyceryliminodiacetic acid,        glycinamidedisuccinic acid, glycoletherdiaminetetraacetic acid,        2-hydroxyethyldiacetic acid, hydroxyethylenediaminetriacetic        acid, hydroxyiminodiacetic acid, iminodiacetic acid,        iminodisuccinic acid, lauroyl ethylene diamine triacetic acid,        methylglycinediacetic acid, methyliminodiacetic acid,        nitrilotriacetic acid, nitrilotripropionic acid, salicylic acid,        serinediacetic acid (or salts thereof) or combinations thereof;        and    -   a potassium-containing salt, a sodium-containing salt or a        combination thereof (preferably a potassium-containing salt).

In another embodiment a composition of the invention may comprise:

-   -   a transition metal chelate formed from a transition metal (e.g.        selected from iron, copper, or mixtures thereof) and a chelating        agent selected from diamino cyclohexane tetra-acetic acid,        ethylenediaminedisuccinic acid, ethylenediaminetetraacetic acid,        ethanol-diglycine, hydroxyethylenediaminetriacetic acid,        methylglycinediacetic acid, glutamic-acid diacetic acid,        diethylenetriaminepentaacetic acid, iminodisuccinic acid, their        salts, and combinations thereof; and    -   a potassium-containing salt, a sodium-containing salt or a        combination thereof (preferably a potassium-containing salt).

In a further embodiment a composition of the invention may comprise:

-   -   an active ingredient (e.g. in a herbicidal effective amount) in        the form of one of, or a mixture of, iron hydroxyethylene        diaminetriacetate, iron ethylenediamine tetraacetate, iron        ethylene diamine disuccinate, and iron glutamicacid diacetate;        and a potassium-containing salt, a sodium-containing salt or a        combination thereof (preferably a potassium-containing salt).

In a yet further embodiment a composition of the invention may comprise:

-   -   an iron chelate (e.g. in a herbicidal effective amount) selected        from the group consisting of iron ethylenediamine tetraacetate        (FeEDTA), iron hydroxyethylenediamine tetraacetate (FeHEDTA),        and combinations thereof.

The invention will now be described, by way of example only, withreference to the following Examples.

EXAMPLES Materials & Methods

Unless otherwise specified, all of the iron solutions were made usingthe same molar concentration of iron ion as chelating agent. In theliquid formulations samples were prepared by diluting a metal chelate,iron HEDTA (Neu 1173H) or iron EDTA to the desired level of iron asspecified using stirring. Neu 1173H contains the stabilizer sodiumcitrate at 1.5% prior to dilution. Dilutions of iron HEDTA to the levelof 0.25% Fe incorporate 0.08% sodium citrate into the spray solutions.KCl was then diluted and added to the diluted metal chelate.

In the dry formulations, the iron chelate was simply blended with KCland with other fertilizer ingredients. Samples were usually preparedwithin 48 hours of treatment. All of the outside tests were done onareas of grass and white clover that were at least 2 months old. For thegreenhouse tests, white clover and dandelion were grown in a commercialgreenhouse mix using supplemental lighting and heating. Each plant wasgrown in a 2¼ inch pot to a minimum diameter of 15-20 cm. Perennialryegrass was grown in 2¼ inch pots in the same greenhouse conditions asabove and they are at least 4 weeks old at the time of application.Field and greenhouse trials had at least two and ten replicatesrespectively. All of the liquid solutions were sprayed onto the plantsat a rate of 100 or 200 ml/m² using a handheld trigger sprayer. With dryformulations the granules were applied with a shaker to the plantsurface at 50 to 80 g/m².

All plant damage was visually assessed using a percentage rating scalefrom 0 (no injury) to 100% (death). A damage rating of 40% or higher isconsidered high enough to control undesired plants. Percentage controlwas calculated from the respective weed cover data (e.g. preferablyusing the Henderson & Tilton formula).

Example 1

Greenhouse Dandelion and Turf Test of Iron Chelates with PotassiumChloride

All of the iron chelates (0.25% Fe) and the potassium chloride weresprayed twice at a volume of 200 ml/m² on to 0.25 m² of perennialryegrass and dandelion. Observations were made 7 days after secondspraying. The results are shown in Table 1 below.

TABLE 1 Grass Damage (%) Dandelion Damage (%) FeHEDTA 1.5% a.i. 6 63(0.25% Fe) FeHEDTA 1.5% a.i. 9 89 (0.25% Fe) + KCl 2% Untreated 0 0

Example 2

Field White Clover and Turf Test of Iron Chelates with PotassiumChloride

All of the iron chelates (0.25% Fe) and the potassium chloride weresprayed twice at a volume of 200 ml/m² on to 0.25 m² of perennialryegrass and white clover. Observations were made 28 days after secondspraying. The results are shown in Table 2 below.

TABLE 2 Grass Damage (%) White Clover control (%) FeHEDTA 1.5% a.i. 6 40(0.25% Fe) FeHEDTA 1.5% a.i. 7 81 (0.25% Fe) + KCl 1.5% Untreated 0 0

Example 3

Greenhouse Dandelion and Turf Test of Iron Chelates with PotassiumChloride

All of the iron chelates (0.8% Fe) and the potassium chloride weresprayed twice at a volume of 100 ml/m² on to 0.25 m² of perennialryegrass and dandelion. Observations were made 7 days after secondspraying. The results are shown in Table 3 below.

TABLE 3 Grass Damage (%) Dandelion damage (%) FeEDDS 4.98% a.i. 1 58(0.8% Fe) FeEDDS 4.98% a.i. 0 88 (0.8% Fe) + KCl 1% Untreated 0 0

Example 4

Greenhouse White Clover and Turf Test of Iron Chelates with PotassiumChloride

All of the iron chelates (0.25% Fe) and the potassium chloride weresprayed twice at a volume of 200 ml/m² on to 0.25 m² of perennialryegrass and white clover. Observations were made fourteen days afterfirst spraying. The results are shown in Table 4 below.

TABLE 4 Grass Damage (%) White Clover Damage (%) FeEDTA 1.78% a.i. 0 47(0.25% Fe) FeEDTA 1.78% a.i. 0 74 (0.25% Fe) + KCl 2% Untreated 0 0

Example 5

Greenhouse White Clover and Turf Test of Iron Chelates with PotassiumChloride

All of the iron chelates (0.25% Fe) and the potassium chloride weresprayed twice at a volume of 100 ml/m² on to 0.25 m² of perennialryegrass and white clover. Observations were made seven days after firstspraying. The results are shown in Table 5 below.

TABLE 5 Grass Damage (%) White Clover Damage (%) FeHEDTA 1.5% a.i. 4 58(0.25% Fe) KCl 2% 0 0 FeHEDTA 1.5% a.i. 4 82 0.25% Fe + KCl 2% Untreated0 0

Example 6

Greenhouse White Clover and Turf Test of Iron Chelates with PotassiumChloride

All of the iron chelates (0.25% Fe) and the potassium chloride weresprayed twice at a volume of 200 ml/m² on to 0.25 m² of perennialryegrass and white clover. Observations were made two days after firstspraying. The results are shown in Table 6 below.

TABLE 6 Grass Damage (%) White Clover Damage (%) FeEDTA 1.78% a.i. 0 18(0.25% Fe) FeEDTA 1.78% a.i. 1 54 (0.25% Fe) + KCl 2% Untreated 0 0

Example 7

Greenhouse White Clover and Turf Test of Iron Chelates with PotassiumChloride

All of the iron chelates (0.25% Fe) and potassium chloride were sprayedtwice at a volume of 200 ml/m² on to 0.25 m² of perennial ryegrass andwhite clover. Observations were made seven days after first spraying.The results are shown in Table 7 below.

TABLE 7 Grass Damage (%) White Clover Damage (%) FeEDTA 1.78% a.i. 0 24(0.25% Fe) FeEDTA 1.78% a.i. 0 55 (0.25% Fe) + KCl 1.5% Untreated 0 0

Example 8

Field Dandelion and Turf Test of Dry Composition of Iron Chelates withPotassium Chloride

The granules containing iron chelates (0.9% Fe) plus potassium chloride(20%) were applied as an RTU granule twice at the rate of 50 g/m² on to0.25 m² of perennial ryegrass and dandelion. Observations were madeseven days after second application. The results are shown in Table 8below.

TABLE 8 Grass Damage (%) Dandelion damage (%) Dry FeHEDTA 7% 3 65 (0.98%Fe) Dry FeHEDTA 7% 3 81 (0.98% Fe) + potassium chloride 20% Untreated 00

Example 9

Greenhouse Dandelion Test Dry Composition of Iron Chelates withPotassium Chloride

All of the iron chelates (0.9% Fe) and the potassium chloride wereapplied once at the rate of 50 g/m² on to dandelion. Observations weremade twenty eight days after application. The results are shown in Table9 below.

TABLE 9 Dandelion damage (%) Dry FeHEDTA 7% 57 (0.9% Fe) + powderedsugar 20% + corncob 73% Dry FeHEDTA 7% 82 (0.98% Fe) + potassiumchloride 20% + corn cob 73% Untreated 0

Example 10

Greenhouse Dandelion and Turf Test of Iron Chelates with Sodium Sulfate

All of the iron chelates (0.25% Fe) and sodium sulfates were sprayedonce at a volume of 200 ml/m² on to 0.25 m² of perennial ryegrass anddandelion. Observations were made six days after first spraying. Theresults are shown in Table 10 below.

TABLE 10 Grass Damage (%) Dandelion damage (%) FeHEDTA 1.5% a.i. 4 35(0.25% Fe) FeHEDTA 1.5% a.i. 4 95 (0.25% Fe) + Na₂SO₄ 2% Na₂SO₄ 2% 4 0Untreated 0 0

All publications mentioned in the above specification are hereinincorporated by reference. Various modifications and variations of thedescribed methods and system of the present invention will be apparentto those skilled in the art without departing from the scope and spiritof the present invention. Although the present invention has beendescribed in connection with specific preferred embodiments, it shouldbe understood that the invention as claimed should not be unduly limitedto such specific embodiments. Indeed, various modifications of thedescribed modes for carrying out the invention which are obvious tothose skilled in chemistry, biochemistry and biotechnology or relatedfields are intended to be within the scope of the following claims.

1. A herbicidal composition comprising: a. a transition metal chelate;and b. a potassium-containing salt and/or a sodium-containing salt;wherein said composition has enhanced herbicidal activity when comparedwith an otherwise identical composition lacking saidpotassium-containing salt and/or said sodium-containing salt.
 2. Acomposition according to claim 1, wherein said composition has enhancedselective herbicidal activity when compared with an otherwise identicalcomposition lacking said potassium-containing salt and/or saidsodium-containing salt.
 3. Use of a potassium-containing salt and/or asodium-containing salt, for enhancing herbicidal activity of atransition metal chelate.
 4. Use of a potassium-containing salt and/or asodium-containing salt, for enhancing selective herbicidal activity of atransition metal chelate.
 5. A herbicidal composition or use accordingto any one of the preceding claims, wherein the potassium-containingsalt is potassium chloride, potassium sulfate, potassium phosphate,potassium citrate, potassium carbonate, potassium biphosphate, potassiumnitrate, potassium thiosulfate, potassium amino acid complex, potassiumoctanoate (KC8), potassium decanoate (KC10), potassium octadecanoate(KC18), or combinations thereof.
 6. A herbicidal composition or useaccording to any one of the preceding claims, wherein thesodium-containing salt is selected from sodium chloride, sodium acetateanhydrous, sodium acetate trihydrate, sodium benzoate, sodiumbicarbonate, sodium bisulphite, sodium borate decahydrate, sodiumbromide, sodium chlorite, sodium nitrate, sodium nitrite, sodiumsilicate, sodium sulfate, sodium sulfite, or sodium tripolyphosphate,sodium chloroacetate, sodium chlorate, sodium metabisulfite, sodiumoctanoate (NaC8), sodium nonanoate (NaC9), sodium decanoate (NaC10),sodium octadecanoate (NaC18) or combinations thereof.
 7. A herbicidalcomposition or use according to any one of the preceding claims, whereinthe potassium-containing salt is potassium chloride.
 8. A herbicidalcomposition or use according to any one of the preceding claims, whereinthe sodium-containing salt is sodium sulfate.
 9. A herbicidalcomposition or use according to any one of the preceding claims, whereinthe transition metal is iron, copper, manganese, nickel, zinc orcombinations thereof.
 10. A herbicidal composition or use according toany one of the preceding claims, wherein the transition metal is ferriciron, ferrous iron, or a combination thereof.
 11. A herbicidalcomposition or use according to any one of the preceding claims, whereinthe transition metal chelate comprises an aminopolycarboxylate chelatingagent, preferably selected from hydroxyethylenediaminetriacetic acid,ethylenediaminetetraacetic acid, diamino cyclohexane tetraacetic acid,ethylenediamine disuccinic acid, ethanoldiglycine, methylglycinediaceticacid, glutamicaciddiacetic acid, or combinations thereof and/or saltsthereof.
 12. A herbicidal composition or use according to any one of thepreceding claims, wherein the metal chelate comprises ironhydroxyethylenediaminetriacetic acid, iron ethylenediaminetetraaceticacid, iron gluconic acid, iron glutamicaciddiacetic acid, ironethylenediamine disuccinate, iron methylglycinediacetate, iron aminotri(methylenephosphonic acid), iron ethanoldiglycine, ironhydroxyethyldiphosphonic acid, iron iminodisuccinic acid, iron hydroxyiminodisuccinic acid or combinations thereof.
 13. A herbicidalcomposition or use according to any one of the preceding claims, whereinthe transition metal chelate comprises or consists of iron hydroxyethylenediamine triacetate.
 14. A herbicidal composition or useaccording to any one of claims 1-13, wherein the transition metalchelate comprises or consists of iron ethylenediaminetetraacetate.
 15. Aherbicidal composition or use according to any one of claims 1-13,wherein the transition metal chelate comprises or consists of ironethylene diamine disuccinate.
 16. A herbicidal composition or useaccording to any one of claims 1-13, wherein the transition metalchelate comprises or consists of iron glutamicacid diacetate.
 17. Aherbicidal composition or use according to any one of the precedingclaims, wherein the metal chelate is present at a concentration betweenabout 1.0% to about 12.0% by weight.
 18. A herbicidal composition or useaccording to any one of the preceding claims, wherein thepotassium-containing salt and/or sodium-containing salt is present at aconcentration of about 0.5% to about 25.0% by weight.
 19. A herbicidalcomposition or use according to any one of the preceding claims, whereinthe transition metal (preferably iron) as a metal chelate is present ata concentration of about 0.18% to about 5.0% by weight.
 20. A herbicidalcomposition or use according to claim 19, wherein the transition metal(preferably iron) as a metal chelate is present at a concentration ofabout 0.2% to about 1.5% by weight.
 21. A method for controlling thegrowth of undesired vegetation, said method comprising: a. providing atransition metal chelate; and a potassium-containing salt and/or asodium-containing salt; and b. contacting undesired vegetation with saidtransition metal chelate and said potassium-containing salt and/or saidsodium-containing salt, and wherein, following said contacting step, theundesired vegetation is destroyed.
 22. A method for selectivelycontrolling the growth of undesired vegetation, said method comprising:a. providing a transition metal chelate; and a potassium-containing saltand/or a sodium-containing salt; and b. contacting desired and undesiredvegetation with said transition metal chelate and saidpotassium-containing salt and/or said sodium-containing salt; andwherein, following said contacting step, the undesired vegetation ispreferentially destroyed while growth of the desired vegetation isrelatively unharmed.
 23. The method according to claim 21, wherein saidmethod comprises providing a composition according to any one of claim1-2 or 5-20, and contacting said undesired vegetation with saidcomposition.
 24. The method according to claim 22, wherein said methodcomprises providing a composition according to any one of claim 1-2 or5-20, and contacting said desired and undesired vegetation with saidcomposition.
 25. The method according to claim 22 or claim 24, whereinthe method provides an enhanced selective herbicidal effect whencompared with an otherwise identical method lacking inclusion of saidpotassium-containing salt and/or said sodium-containing salt.
 26. Themethod according to any one of claims 21 to 25, wherein the transitionmetal chelate and the potassium-containing salt and/or sodium-containingsalt are applied to a grass lawn.
 27. The method according to any one ofclaims 21 to 26, wherein said undesired vegetation comprises or consistsof dandelions, daisies, chickweed, mosses, liverworts, ferns,horsetails, conifers, dicotyledonous plants, algae or combinationsthereof.
 28. The method according to any one of claims 21 to 27, whereinthe transition metal chelate is selected from iron hydroxyethylenediaminetriacetate, iron ethylenediamine tetraacetate, iron ethylenediamine disuccinate, iron glutamicacid diacetate or combinationsthereof.
 29. The method according to claim 28, wherein the iron that ispresent in the iron chelate is applied to an area comprising desired andundesired vegetation at a rate of between 0.20 to 1.8 g Fe/m².
 30. Themethod according to claim 29, wherein the iron that is present in theiron hydroxyethylene diaminetriacetate is applied to an area comprisingdesired and undesired vegetation at a rate of between 0.20 to 1.8 gFe/m².
 31. The method according to claim 29, wherein the iron that ispresent in the iron ethylenediamine tetraacetate is applied to an areacomprising desired and undesired vegetation at a rate of between 0.20 to1.8 g Fe/m².
 32. The method according to claim 29, wherein the iron thatis present in the iron ethylene diamine disuccinate is applied to anarea comprising desired and undesired vegetation at a rate of between0.20 to 1.8 g Fe/m².
 33. The method according to claim 29, wherein theiron that is present in the iron glutamicacid diacetate is applied to anarea comprising desired and undesired vegetation at a rate of between0.20 to 1.8 g Fe/m².